FIELD OF THE INVENTION
The invention lies in the automotive technology field. More specifically, the invention pertains to an intake device for an internal combustion engine. The intake device includes a collector or first manifold, which takes in ambient air via an intake connection. Inlet pipes connect the collector to inlets into the cylinders of the internal combustion engine and are disposed closely adjacent one another in a portion between the collector and the cylinders and are formed in their walls with mutually facing, adjacent openings. The openings are selectively opened or closed by at least one control flap with a shaft controlled by a control device.
International publication WO 96/07022 discloses an intake device which comprises inlet pipes that branch off from a collector and lead into inlets of cylinders of the internal combustion engine. Furthermore, the intake device has control flaps, which are respectively arranged in an opening between two inlet pipes and are mounted so as to be pivotable. If the control flaps are pivoted in such a way that the openings are closed, the effective length of the inlet pipes, that is the length over which the gas column in the inlet pipe oscillates, corresponds to the length of the inlet pipes from the collector to the inlets of the cylinders. If the control flaps are pivoted in such a way that the opening is opened, the effective length of the inlet pipes corresponds to the distance from the opening up to the inlets of the cylinders. Depending on measured values of the operating variables of the internal combustion engine, one of the two effective lengths of the inlet pipes is set. Thus, the charging of the cylinders can be improved and the maximum torque can therefore be increased.
Bearing collars are provided at the opening against which the control flap comes to bear when it is pivoted in such a way as to close the opening.
The intake system is a substantial source of engine noise and automotive technology is subject to increasingly stringent statutory provisions which establish the limit values for the amplitude of the sound waves produced by motor vehicles.